Steam generator



Jan. 27, 1948. G. A. REHM STEAM GENERATOR 2 Sheets-Sheet l` Filed Nov. 16, 1944 ooooo ooooooooo oooooooo o o o o o o o O O O O O 4900 o oooooo/O oooooo OOO ooooooo ooo Oooo x A A V m w G .Jan. 27, 1948. G. A. REHM STEAM GENERATOR 2 Sheets-Sheet 2 Filed Nov. 16, 1944 Patenta& Jan. 27, 1948 ESVTAT ES %PATENT "OFF ICE STEAM GENERATOR :Gustav Rehn, Worcester, Mass assignor fto `Riley StokeriCorporation,?Worcestenl Mass.,-..a

corporaton. of* Massachusetts Appli'cation' November 16:1944; Serial"No."5B3;653

JClaims. (Cl. 122 347) 1 This invention relates to-steamgeneratorsand morepartcularly to steamagenerators of the -Wa- A ter tube type `having a combustiomchamber provided with water-cooled` side Wallis.

.One form of ;steam;generator .inrcommonuse comprises upper and' lower x longitudi-nals drums connected by a'bank, of uprighhwater tubes,` a

- combustion chamber inront i of the tube bank,

upright water Wall tubes-associated with the side .walls of the combustion .chambe and communicatingat their Vupper endswith the .uppers drum,

and longitudinal 'headers connected to the-lower ends of the water wall tubes. 'Inor'der to complete a path for circulation f water. through the water wall tubes; two con'strudtionshave been utilized' heretofore. 'In one f. theseprioncon- 'structions the headers hav been. connected to the lower drum; but since sdiment tends to settlein this'drum' by gravity 'thereis 'danger of.. supplying dirtyxwater to the highly heatedmater wall tubes unless care' is taken' to Operatethe boiler blowdownsystem at properpintervals. Inthe other of these prior .constructions rows n of "water u tubes have eXtended laterally from opposite sides-of the upper drum and' thencefidownwardly along the i. side walls of the setting toconnectr withfthe rear tpor-tions of the' headers;` but if the water level in theupper drum should drop-onlyslightly the supply of. water tothe headers ;and Waterwalk tubes 'would' fail entirely. This would-resultpin overheating of the swater -wa11 tubes and `-serious dam age thereto.

:It is accordingiyoneobject of the invention to avoidthese dificulties with-priorsteam generators .of the general 'type discussed' above=bwproviding an improved cireulating ;path tonsupplying water to thewater -wall tubes.

be apparent to* 'those` 'skilled" 'in' the art; theiin- *ven-hon* resides 'in- 'the combination of partsisetv forthinthe specification 'and"covered"by""the claims append'e'd' hereto.

Referring to the drawings-illustrating one embodimentsof the invention, and in which like reference numerals indicate like parts,

2 Figr lis-a longitudinal section througha steam generator, taken on the line lof Fig.- 2;

Fig. 2 -is--a -section taken on the -line 2-2- =of .Eig..1;

Fig. 3 -is a seotiontaken -on the line 3-3-of zFigr2;

Fig. -is a `sectontaken on the :line v 4- of 'Fign- 2 and r Fig..-5 is a fragmentary detail-'in plan showing a portion- 'of the water waliheader Construction. The embodiment'illustrated comprises a setting havinga -front wa11- & opposed side walls I I,` and a rear--wall- 12. `In the rear portionofthe setting there is providedalongitudi-nal 'upper steam-'and- --Water drum `I 4, 3; longitudinal 'lower Water `*drum !5, and a bank- -of` upright Water tubes l connectingthe drums andsarranged in transverse rows to form-a convection heating surface. The -f-ront portion of the setting encloses a combustion-chamber !8 intowhich fuel and air-may be delivered througha suitable-burner-opening !9 in s the front wall [0. Three uprig ht transverse-baffies 20 are mounted in thetubebank IG to direct the hot. gases in a' tortuous course as they flow rear-wardly from thecombustion chamber and. into .contact with the water tubes, the gases fically.escaping through` outlet duets--Zl at the rear of .thesetting. Thegasesmake four -passes .overthe water tubes before reaching the outlet ducts. Thefourthor rearmostgas passis employed as an economizer to heat theincoming feed water, and orthis purpose an upr ight partition 23 is mounted withinthe lower -drum' !5 directly-beneath the rearmost-bafiie 20. Also,- the feed :Wateris delivered to the rear portionof the upper drum !4 and behind a partition za therein by --means of-a pipez this .partition joining the lower wall of the drum between two of the trans- `verse rowsof'- tubes in` the rear gas pass. Consequently the eedwater-is compelled .to d'escend through the rearmost tubes to the lower drum lsand then flow upwardly through the tubes -in theront portion u of the rear-gas pass before- A. rate. r For :this-purpose a-longitudinal lowerhead er-'30 extends along the lower--portion of each side-wall: i I and a longitudinal upper :header ;3 l

u extends along :the top of `each& side zwall. -Upright water wall tubes 32 extend upwardly from the lower headers 30 and adjacent the side walls H, the upper portions of these tubes being bent inwardly to cross one another above the center of the combustion chamber !8 and support the roof 34 thereof, the upper ends of the tubes being connected to the upper headers 3 I. Releaser tubes 35 connect the upper headers with the front end of the upper drum !4, preferably above the normal water level. At the rear of the combustion chamber !8, the two lower headers 30,

are connected by a transverse header 31 from which two rows of water tubes 38 extend upwardly to enter the upper drum [4 in circumferential rows. These tubes'- 38 support arefractory bridge wall 39 which shields the lower drum.

15 from the radiant heat of the furnace; The junction between each longitudinal header 30`a'nd the transverse header 31 may be eflected by means of a welding T 40, as shown in Fig. 5.

It is of great importance to ensure a continuous and adequate supply of clean water to the lower headers 30 and 31. Even a momentary interruption to such' supplymay 'result in overheating of the water tubes 32 and 38, for these tubes are subjected to radiant heat and theygenerate steam at a very high rate. Accordingly I provide means for' supplying these headers directly from the bottom of the upper drum l4,

which is less likely to contain Suspended insoluble r i matter than the lower' drum. For this purpose some of the boiler Water tubes IE are preferably omitte'd 'at thecenter of thethird gas pass to provide a space 42 beneath the upper drum 14,

with groups of tubes 16 on Qppsitesi'des of this V 3 space. `Within the space 42 there areprovided upright water tubes 43 with their upper end connected to the bottom oi the upper drum 14, close to the vertical axi'cl` plane thereof, and their lower portions bent laterally outward to extend between the lower portions of the adjacent tubes IE and connect with the rear portions of the lower headers 30. Thetubes 43 are appreciably larger in diameter than the tubes !6, and the i rows of tubes !Sat the sides of the space 42 are, spaced apart rather widely to avoid any interierence with the laterally extending lower portions of the tubes 43. Since the tubes 43 are remote `from the combustion chamber IB and in ,a region of comparatively low gas temperature, they serve as very efiective downcomers to ensure an adequate supply of water to the headers 30 and 31. This supply will be maintained in spite of wide fiuctuations in the water level in the drum l4, and in fact 'as longas there is any water in this drum, since the downcomer tubes are connected 4 of the tube bank, walls providing a combustion chamber in front of the tube bank, longitudinal headers on opposite sides of the combustion chamber, downcomer tubes located within the said space with their upper ends connected to the bottom of the upper drum close to the vertical xia plane thereof, the lower ends of the downcomer tubes'being connected to the rear portions of the headers, and upright water wall tubes adjacent the side walls of the combustion chamber with their lower ends connected to the headers and their upper ends communicating with the steam-and-water drum.

2. A steam generator comprising a longitudinal steam-and-water' drum, a longtudinal water drum therebeneath, a. bank of upright water tubes connecting the drums and arranged to leave a space free from such tubes in a region located a substantial distance rearwardly from the front of the tube bank, there being groups of said water v tubes on opposite sides of the said space, walls providing a combustion chamber in front of the tube bank, lon'gitudinal headers on opposite si'des of the combustion chamber, downcomer tubes having upright portions located in the said space and connected at their upper ends to the bottom [of the upper drum, the lower portions of the downcomer tubes being bent laterally outward to extend between the tubes of said groups and connect with the rear portions of the headers, and

V upright water wall tubes adjacent the side walls of the combustion chamber with their lower ends f connected to the headers and their upper ends communicating with the steam-and-water drum. 3.` A steam generator comprising a longitudlnal steam-and-water drum, a longitudinal water drum therebeneath, a bank of upright water tubes connectingthe drums and arranged to leave a space free from such tubes in a region located a substantial distance rearwardly -from the front of the tube bank, walls providing a combustion chamber in front of the, tube bank, longtudinal headers on opposite sides of the combustion chamber, downcomer tubes located within the said space with their upper ends connected to the b ttom of the ,upper drum close to the vertical to the bottom of the drum. consequently a, rapid e circulation of clean water will be maintained through the' water wall tubes 32 and the bridge wall tubes 38 at all times during the operation of the boiler. By providing the free space 42 for the downcomer tubes 43, adequate ligament strength is obtained between the tube holes in the drum !4 and removal of tubes for replace- "ment is -facilitated if this should ever become necessary Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A steam generator comprising a longitudinal steam-and-water drum, a longitudinal water drum therebeneath, a bank of upright water tubes connecting the drums and arranged to leave a space' free from such tubes in a region located :ajsubstantial distance rearwardly from the ,front EEFERENCES CITED The following references are of record in the file'of this patent:

UNITED STATES PATENTS Number Name Date 2,228,590 Badenhausen J an. 14,1941 2,322,390 Rehm June 22, 1943 2,09'7,268` Best Oct. 26, 1937 2,222,530 Davey Nov. 19, 1940 FOREIGN PATENTS Number Country Date 541159 Great Britain Aug. 17, 1942 Disclaimer 2,435,055. Gustav A. Rehm, Worcester, Mass. STEAM GENERATOR. Patent dated Jan. 27, 1948. Disclaimer filed Mar. 15, 1950, by the assignee, Riley Stolcer Corporation.

Hereby enters this disclaimer to claim 1 of said patent.

[Qfical Gazette April 11, 1950.] 

